JP6644891B2 - Lithographic apparatus having active base frame support - Google Patents

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application claims the priority of European Patent Application No. 15201466.8, filed December 21, 2015, which is incorporated herein by reference in its entirety.

The present invention relates to a lithographic apparatus having an active base frame support.

  A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such cases, a patterning device, which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (eg comprising part of one or several dies) on a substrate (eg a silicon wafer). The transfer of the pattern is usually performed by imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Conventional lithographic apparatuses synchronize a substrate parallel or anti-parallel with a given direction (the "scan" direction) with a so-called stepper, where each target portion is illuminated by exposing the entire pattern to the target portion in one go. A so-called scanner, in which each target portion is illuminated by scanning the pattern with a beam of radiation in a given direction (the "scan" direction) while scanning. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern on the substrate.

  In a lithographic apparatus, a support, such as a substrate support or a patterning device support, moves during operation to perform, for example, a scanning operation. The support is provided with an actuator, such as one or more electric motors, for example a planar motor. Actuators can include, for example, a combination of a short stroke actuator that accurately positions a smaller movement range and a long stroke actuator that positions a larger movement range. The actuator moves the support relative to the balance mass. Since the center of gravity of the support (plus the substrate or patterning device held by the support) does not coincide with the center of gravity of the balance mass, the resulting opposing forces on the balance mass may torque the balance mass. The support is positioned over the balance mass when a horizontal force by the actuator, for example, a force in the x or y direction, imparts an opposing force and a torque about each of the y and x directions to the balance mass ( That is, there is a possibility of being separated in the Z direction). The X and Y directions are defined as forming a horizontal plane perpendicular to the Z direction.

  The balance mass is supported by a base frame of the lithographic apparatus, which in turn is supported by a ground plane (e.g., ground floor, pedestal, etc.) of the building in which the lithographic apparatus is located.

  The effects of vibration, torque and counter-movement tend to disturb the positioning of the support, which can result in overlay errors of the lithographic apparatus.

  Even without a balance mass, the movement of the support can cause disturbance forces on the base frame of the lithographic apparatus. Due to the lack of the balancing effect of the balance mass, the disturbance force applied to the base frame may be further increased.

  It is desirable to have an accurate positioning of the support.

According to an embodiment of the present invention, there is provided a lithographic apparatus, comprising:
A base frame constructed to form a support structure of the lithographic apparatus;
An active base frame support configured to support the base frame on a ground plane, the active base frame support including an actuator configured to exert a horizontal force on the base frame;
Lithographic apparatus
A lithographic apparatus is provided, further comprising a control device configured to drive the actuator based on a signal representing a force applied to the base frame.

Embodiments of the present invention will be described below with reference to the accompanying schematic drawings, in which corresponding reference numerals indicate corresponding parts, but this is by way of example only.

1 shows a lithographic apparatus in which the invention can be implemented. FIG. 4 illustrates a schematic side view of an active base frame support for use in a lithographic apparatus according to an embodiment of the present invention. FIG. 3 illustrates a highly schematic side view of a portion of a lithographic apparatus according to an embodiment of the present invention. FIG. 4 shows a highly schematic side view of a part of a lithographic apparatus according to another embodiment of the invention. FIG. 4 shows a time diagram of a base frame oscillation to show the effect of the embodiment of the invention described with reference to FIG. FIG. 4 shows a time diagram of a base frame oscillation to show the effect of the embodiment of the invention described with reference to FIG. FIG. 4 shows a time diagram of a base frame oscillation to show the effect of the embodiment of the invention described with reference to FIG. 3.

  FIG. 1 schematically shows a lithographic apparatus according to one embodiment of the invention. The apparatus supports an illumination system (illuminator) IL configured to condition a radiation beam B (eg, UV radiation or any other suitable radiation) and a patterning device (eg, a mask) MA. A mask support structure (eg, a mask table) MT constructed and connected to a first positioning device PM configured to accurately position the patterning device according to specific parameters. The apparatus also includes a substrate table configured to hold a substrate (eg, a resist-coated wafer) W and connected to a second positioning device PW configured to accurately position the substrate according to specific parameters. (Eg, wafer table) including WT or “substrate support”. The apparatus includes a projection system (eg, a refractive projection) configured to project a pattern imparted to the radiation beam B by a patterning device MA onto a target portion C (eg, including one or more dies) of a substrate W. Lens system) PS.

  The illumination system may include a refractive, reflective, magnetic, electromagnetic, electrostatic, or other type of optical component, or any combination thereof, for directing, shaping, or controlling radiation. Various types of optical components can be included.

  The mask support structure supports, ie bears the weight of, the patterning device. The mask support structure holds the patterning device in a manner that depends on conditions such as the orientation of the patterning device, the design of the lithographic apparatus, and the like, for example, whether or not the patterning device is held in a vacuum environment. The mask support structure can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The mask support structure may be a frame or a table, for example, which may be fixed or movable as required. The mask support structure may ensure that the patterning device is at a desired position, for example with respect to a projection system. Any use of the terms "reticle" or "mask" herein may be considered synonymous with the more general term "patterning device."

  The term "patterning device" as used herein is broadly interpreted as referring to any device that can be used to pattern a cross-section of a radiation beam so as to create a pattern on a target portion of the substrate. It should be. It should be noted here that the pattern imparted to the radiation beam may not correspond exactly to the desired pattern in the target portion of the substrate, for example when the pattern includes phase shifting features or so-called assist features. Generally, the pattern imparted to the radiation beam will correspond to a particular functional layer in a device being created in the target portion, such as an integrated circuit.

  The patterning device may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography, and include mask types such as binary masks, alternating phase shift masks, attenuated phase shift masks, as well as various hybrid mask types. It is. As an example of a programmable mirror array, a matrix arrangement of small mirrors is used, each of which can be individually tilted to reflect an incoming radiation beam in different directions. The tilted mirror imparts a pattern to the radiation beam reflected by the mirror matrix.

  As used herein, the term "projection system" is used to refer to the exposure radiation used, or other factors, as appropriate, e.g., refractive optical systems, reflective optical systems, reflective optical systems, etc. It should be construed broadly to cover any type of projection system, including refractive, magneto-optical, electromagnetic and electrostatic optical systems, or any combination thereof. Any use of the term "projection lens" herein may be considered as synonymous with the more general term "projection system".

  As shown herein, the apparatus is of a transmissive type (eg employing a transmissive mask). Alternatively, the apparatus may be of a reflective type (eg using a programmable mirror array of a type as referred to above, or using a reflective mask).

  The lithographic apparatus may be of a type having two (dual stage) or more substrate tables or “substrate supports” (and / or two or more mask tables or “mask supports”). In such a "multi-stage" machine, additional tables or supports may be used in parallel or one or more tables or supports may be used while one or more other tables or supports are used for exposure. Preliminary steps can be performed.

  The lithographic apparatus may be of a type wherein at least a portion of the substrate may be covered by a liquid having a relatively high refractive index, such as water, so as to fill a space between the projection system and the substrate. The immersion liquid may also be applied to other spaces in the lithographic apparatus, for example, between the mask and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of projection systems. As used herein, the term "immersion" does not mean that a structure, such as a substrate, must be submerged in the liquid, but rather that liquid exists between the projection system and the substrate during exposure. .

  Referring to FIG. 1, the illuminator IL receives a radiation beam from a radiation source SO. The source and the lithographic apparatus may be separate components, for example when the source is an excimer laser. In such a case, the radiation source is not considered to form part of the lithographic apparatus, and the radiation beam is illuminated from the source SO by the aid of a beam delivery system BD comprising, for example, a suitable directing mirror and / or a beam expander. Passed to IL. In other cases, the source may be an integral part of the lithographic apparatus, for example when the source is a mercury lamp. The source SO and the illuminator IL, together with the beam delivery system BD if required, can be referred to as a radiation system.

  The illuminator IL may include an adjuster AD set to adjust the angular intensity distribution of the radiation beam. Typically, the outer and / or inner radial extent (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution in a pupil plane of the illuminator can be adjusted. In addition, the illuminator IL may include various other components such as the integrator IN and the capacitor CO. The illuminator may be used to condition the radiation beam to achieve the desired uniformity and intensity distribution over its cross section.

  The radiation beam B is incident on a patterning device (eg, mask MA) held on a mask support structure (eg, mask table MT) and is patterned by the patterning device. The radiation beam B traversing the mask MA passes through a projection system PS, which focuses the beam onto a target portion C of the substrate W. With the help of a second positioning device PW and a position sensor IF (eg, an interferometer device, a linear encoder or a capacitive sensor), the substrate table WT is accurately positioned, for example, to position various target portions C in the path of the radiation beam B. Can be moved to Similarly, using the first positioning device PM and another position sensor (not explicitly shown in FIG. 1), the path of the radiation beam B may be determined after mechanical removal from the mask library or during scanning. The mask MA can be accurately positioned. In general, movement of the mask table MT can be realized with the aid of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which form part of the first positioning device PM. Similarly, movement of the substrate table WT or “substrate support” can be realized using a long-stroke module and a short-stroke module forming part of the second positioner PW. In the case of a stepper (as opposed to a scanner) the mask table MT may be connected to a short-stroke actuator only, or may be fixed. The mask MA and the substrate W can be aligned using the mask alignment marks M1, M2 and the substrate alignment marks P1, P2. Although the substrate alignment marks as illustrated occupy dedicated target portions, they may be located in spaces between target portions (known as scribe line alignment marks). Similarly, in situations in which more than one die is provided on the mask MA, the mask alignment marks may be located between the dies.

  The illustrated lithographic apparatus can be used in at least one of the following modes.

  1. In the step mode, the mask table MT or “mask support” and the substrate table WT or “substrate support” are basically kept stationary, while the entire pattern imparted to the radiation beam is projected onto the target portion C at one time. (Ie, a single static exposure). Next, the substrate table WT or "substrate support" is moved in the X and / or Y directions so that another target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure.

  2. In scan mode, the mask table MT or “mask support” and the substrate table WT or “substrate support” are scanned synchronously while the pattern imparted to the radiation beam is projected onto a target portion C (ie a single dynamic exposure). The speed and direction of the substrate table WT or "substrate support" relative to the mask table MT or "mask support" can be determined by the enlargement (reduction) and image inversion characteristics of the projection system PS. In scan mode, the maximum size of the exposure field limits the width (in the non-scan direction) of the target portion in a single dynamic exposure, and the length of the scan operation determines the height (in the scan direction) of the target portion.

  3. In another mode, the mask table MT or "mask support" holds the programmable patterning device and remains essentially stationary, and is applied to the radiation beam while moving or scanning the substrate table WT or "substrate support". The projected pattern is projected on the target portion C. In this mode, the programmable patterning device is updated as needed each time the substrate table WT or "substrate support" is moved, or between successive radiation pulses during a scan, typically using a pulsed radiation source. . This mode of operation is readily available for maskless lithography using a programmable patterning device, such as a programmable mirror array of a type as referred to above.

  Combinations and / or variations on the above described modes of use or entirely different modes of use may also be employed.

  As described above, the actuator moves the support (substrate support or patterning device support) relative to the balance mass. Since the center of gravity of the support is separated from the center of gravity of the balance mass in the Z direction, the resultant opposing force on the balance mass may impart torque to the balance mass. In particular, a horizontal force by the actuator, for example, a force in the X or Y direction, imparts a counterforce in the opposite direction and a torque around each of the Y and X directions to the balance mass.

  Solutions for at least partially compensating for the forces on the balance mass have been devised in the form of active base frame supports. Thereby, the support for supporting the base frame against the ground floor comprises a base frame support actuator such as a piezo actuator or any other actuator such as a motor. The support actuator is configured to exert a vertical (Z) force. Therefore, it is possible to compensate for the torque applied to the base frame resulting from the horizontal movement of the support. That is, when the base frame support actuator exerts a force on the support in the X direction, Ry torque is generated in the balance mass. When the base frame support actuator exerts a force on the support in the y-direction, an Rx torque is created on the balance mass. Such torque on the balance mass can be at least partially compensated for by actuation of the base frame support actuator, with an upward normal force acting on one side of the base frame and a downward force on the other side of the base frame. The at least partial compensation torque can be generated by the application of the normal force. The base frame support actuator can be driven by a suitable control device. A force sensor configured to sense normal force can be included in the base frame support, for example, in the form of a piezo sensor or any other force sensor. The control device can be provided with an output signal of the force sensor, and thus the control device is configured to drive the base frame support actuator in response to the output signal of the force sensor in the (particularly) base frame support. Can be.

  FIG. 2 shows an active base frame support actuator ABSA that includes both a vertical base frame support actuator VBSA and a horizontal base frame support actuator HBSA. In the present embodiment, the base frame support actuator includes, from bottom to top, a vertically stacked piezo stack including a vertical piezo force sensor VBSS, a vertical piezo actuator VBSA, a horizontal piezo actuator HBSA, and a horizontal piezo force sensor HBSS. The horizontal piezo actuator can be, for example, a shear piezo actuator. Accordingly, a piezo stack is provided that allows both vertical sensing and operation and horizontal sensing and operation. Horizontal sensing and actuation can be in a single horizontal direction, such as the X or Y direction. Actuation and sensing in both X and Y directions can be performed, for example, by providing dual horizontal piezo actuators and sensors. Note that the horizontal and vertical actuators can be interchanged, that is, the vertical actuator can be placed above the horizontal actuator. To reduce crosstalk from the actuator to the sensor, mechanical decoupling can be provided between the horizontal actuator and the horizontal sensor. Similarly, mechanical decoupling can be provided between the vertical actuator and the vertical sensor. A protection mechanism may be provided to ensure that the piezo actuator is protected from overload resulting from the force on the actuator piezo element exceeding a maximum value.

  FIG. 3 shows an embodiment to which the active base frame support described with reference to FIG. 2 can be applied. FIG. 3 shows a stage, such as a substrate stage (ie, a substrate table), which in this example is positioned by a short-stroke actuator SSA and a long-stroke actuator LSA, each formed by a motor such as a planar motor. FIG. 3 schematically shows the coil in the movable part of the long stroke actuator and the magnet in the fixed part. Note that embodiments in which the coils and magnets are interchanged are also applicable. The fixed part of the long stroke actuator is supported by the base frame BF. The base frame forms the support structure of the lithographic apparatus. The base frame is then formed (e.g., by a table or ground floor GF) using an active base frame support ABS, such as the four active base frame supports shown in FIG. 2 and described with reference to FIG. ) Supported by the ground plane. Although this example is based on a substrate stage, similar principles apply to any other movable part of the lithographic apparatus, such as a support for supporting a patterning device (such as a mask table) or a support for supporting a reticle mask. it can. Thus, when referring to a stage, substrate table or wafer table in this example, it should be understood that any other support may be contemplated as well.

  The term "horizontal" or "horizontal direction" refers to the direction of a horizontal plane, generally a plane parallel to the ground plane. Correspondingly, the terms "vertical" or "vertical" refer to a direction perpendicular to the horizontal plane, and thus perpendicular to the horizontal. In one embodiment, the horizontal direction in which each of the active base frame actuators is activated and the force sensor measures is the scan direction of the lithographic apparatus, which direction can be defined as the Y direction.

  FIG. 3 furthermore shows the control device C in a highly schematic manner. The control device is supplied with a signal representing a disturbance force applied to the base frame. A drive output of the control device drives the active base frame support actuator in response to a signal representative of a disturbance force. The signal representing the force applied to the base frame can represent a disturbance force such as a horizontal disturbance force. Many embodiments of the signal representing the disturbance force are provided as described in more detail below. For example, as described in more detail below, the signal may be provided on a support setpoint signal, a force sensor signal on a base frame or a force sensor on an active base frame support, an accelerometer on the base frame, a ground floor or a pedestal. And the acceleration signal supplied by the accelerometer. Any combination of the described signals can be provided to the control device, and the control device drives the actuator based on the combination of signals.

  In one embodiment, the control device is provided with an output signal from an active base frame support force sensor at a force signal input FSI. The active base frame support force sensor provides information to the control device about disturbances sensed by the active base frame support. The drive output of the control device drives an active base frame support actuator, such as a Z-direction actuator and / or a horizontal actuator. By combining horizontal force sensing in the active base frame support with horizontal actuation of the active base frame support via a horizontal actuator, horizontal resonance can be damped. Such multiple active base frame supports, for example, each of the four active base frame supports, can be used at the corners or edges of the base frame to similarly prevent rotation about the vertical. Note that the force sensor can be provided on the active base frame support, base frame, or other location.

  In one embodiment, referring to the active base frame support embodiment described with reference to FIG. 2, both the output signal from the vertical force sensor and the output signal from the horizontal force sensor are provided to the control device. Correspondingly, by combining the horizontal and vertical force sensing of the active base frame support with the horizontal and vertical operation of the active base frame support via horizontal and vertical actuators, Resonance as well as rotation about these directions can be damped. If there is more than one active base frame support, one controller can be provided for all four active base frame support systems. The controller receives force sensor inputs from all ABSs, post-acceleration signals from one or more accelerometers, and stage set point information, and distributes output signals to multiple active base frame support actuators.

  Also, at the setpoint input SPI, a support setpoint can be provided to the control device that enables the control device to obtain information regarding the desired position, velocity, and acceleration of the support. Thus, the support setpoint is used as a feedforward signal that provides information about base frame disturbances due to support movement and acceleration.

  Another input signal to the control device can be provided by an acceleration sensor on the base frame. The acceleration signal provided by the acceleration sensor at the acceleration sensor input ASI can provide information about the vibration of the base frame. An accelerometer may be provided, for example, on the base frame and near each of the active base frame supports. Using four active base frame supports at each edge or corner of the base frame, four accelerometers can be provided, one at each edge or corner. Using multiple accelerometers, the control device can take into account information about the excitation of the base frame, such as resonance mode, bending mode, torsion mode, and the like. Accelerometers can be placed near each active base frame support on the base frame, providing an acceleration signal to the control device that is as closely related as possible to the acceleration experienced by the base frame near the base frame support By doing so, more accurate control becomes possible. The number of accelerometers can be greater than 4, especially if it is necessary to measure in the horizontal direction or also in various resonant or torsional modes.

  Using the above inputs, the support setpoint can form a feedforward input signal while the acceleration signal and the force sensor signal provide a feedback input signal, combining feedforward and feedback, and combining feedforward and feedback. Responds quickly to support movements by combining feedforward and feedback accuracy.

  FIG. 4 shows another embodiment in which additional sensors are added to the system described above. Several possible additional sensors that provide a signal representative of the (disturbance) force on the base frame are described below.

  A first possible additional sensor is provided by another accelerometer (another accelerometer FAS), for example another accelerometer provided at or near the structure RES of the lithographic apparatus exhibiting a resonance tendency. For example, a support balance mass such as a substrate stage balance mass may easily resonate. Positioning one or more acceleration sensors in such a structure or at a location where the resonance of such a structure can be detected, the acceleration sensor signal provided to the control device allows the control device to control the active device By configuring the frame support actuator to actuate, the effects of such resonances on the base frame can be damped.

  A second possible additional sensor would be provided in the form of another force sensor FFS, for example a force sensor in a support (eg a wafer stage or a reticle stage) connected to the base frame. The force sensor can be located in a force path towards the base frame. A force sensor signal is provided to the control device at the force sensor input. The control device drives the active base frame support actuator to at least partially compensate for the effect of the force on the base frame. These sensors can be provided, for example, when the support (eg, stage module) is attached to the base frame.

  Yet another additional sensor may be provided in the form of a ground floor accelerometer GFA mounted on the ground floor or pedestal that supports the active base frame support. Such sensors can detect vibrations propagating through the ground floor, such as vibrations from other devices in the environment of the lithographic apparatus, and the effects of such vibrations propagating on the base frame may be controlled. The device may be at least partially damped by receiving a ground floor accelerometer signal at the ground floor accelerometer input and driving the active base frame support to at least partially compensate for the detected vibration. As a result, propagation of such ground floor vibration to the base frame can be significantly suppressed.

  5A-5C show the results of attenuation of the active base frame support, where the active base frame support operates both horizontally and vertically. 5A shows the frequency spectrum of the base frame position in the X direction as a function of frequency, FIG. 5B shows the frequency spectrum of the base frame position in the Y direction as a function of frequency, and FIG. 5C shows the base frame position in the Z direction. Is shown as a function of frequency. 5A, 5B, and 5C show configurations without active base frame support (identified as 1) and configurations with active base frame support with vertical (Z) actuation and sensing, respectively (identified as 2). And an active base frame support (identified as 3) with actuation and sensing in the vertical (Z) and horizontal (Y in this example) directions. In this example, active base frame support is controlled by a combination of feed forward from the support set point and feedback from the base frame acceleration sensor and the active base frame support force sensor. In this example, a stage motion profile is applied as an excitation that causes resonance.

  As can be seen from FIGS. 5A, 5B and 5C, configurations with passive base frame supports exhibit some resonance in the X, Y and Z directions. A configuration with an active base frame support having an actuator in a vertically acting base frame support in combination with a vertically acting force sensor reduces resonance in the X and Z directions while resonance in the Y direction is reduced. Indicates that it will remain. By adding to the base frame support, actuation in the Y direction and corresponding measurement of force in the base frame support in the Y direction reduces resonance in the Y direction, as can be seen in FIG. 5B.

  The configuration with an active base frame support with vertical and horizontal (eg, Y) actuation and sensing can reduce the resonance of the base frame, thus allowing more stable positioning of the base frame, As a result, disturbances occurring on the support during operation are reduced, and thus the positioning of the support becomes more accurate. More accurate positioning of the support may reduce overlay errors in the lithographic process.

  The above principles can be applied to any support. For example, the support can be formed by a substrate table. The support can also be formed by a support of a patterning device such as a mask table. Further, the support can be formed by a reticle mask. Generally, the techniques described in this document can be used to significantly compensate for disturbance forces acting on the base frame. Disturbance forces can arise, for example, from moving parts of the lithographic apparatus that generate a torque on the base frame. In addition, disturbances from other sources, such as disturbances propagating through the ground floor and disturbances caused by resonances in other structures of the lithographic apparatus, can be compensated for using additional sensors.

  Although particular reference is made herein to the use of the lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein has other uses. For example, this is the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, and the like. Any use of the terms “wafer” or “die” herein in light of these alternative applications is considered synonymous with the more general terms “substrate” or “target portion,” respectively. It will be appreciated by those skilled in the art that The substrates described herein may be processed before or after exposure, for example, with tracks (a tool that typically applies a layer of resist to the substrate and develops the exposed resist), metrology tools, and / or inspection tools. be able to. As appropriate, the disclosure herein can be applied to these and other substrate processing tools. Further, the substrate can be processed multiple times, for example, to create a multi-layer IC, so the term substrate as used herein can also refer to a substrate that already contains multiple processed layers.

  Although particular reference has been made to the use of embodiments of the invention in the field of optical lithography, it is to be understood that the invention may be used in other contexts, such as imprint lithography, and is not limited to optical lithography, depending on the context. I want to. In imprint lithography a topography in a patterning device defines the pattern created on a substrate. The topography of the patterning device is imprinted in a layer of resist provided to the substrate, and the resist is cured by applying electromagnetic radiation, heat, pressure, or a combination thereof. The patterning device is removed from the resist, and once the resist has cured, a pattern is left inside.

  As used herein, the terms "radiation" and "beam" refer to ultraviolet (UV) radiation (e.g., 365 nm, 248 nm, 193 nm, 157 nm, or 126 nm, or both) as well as particle beams, such as ion beams or electron beams. It covers all types of electromagnetic radiation, including near-wavelength) and extreme ultraviolet (EUV) radiation (eg, having a wavelength in the range of 5-20 nm).

  The term "lens", where the context allows, may refer to any one or combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic and electrostatic optical components.

  While a particular embodiment of the invention has been described, it will be understood that the invention can be practiced otherwise than as described. For example, the invention relates to a computer program comprising one or more sequences of machine-readable instructions describing a method as disclosed above, or a data storage medium having such a computer program stored therein (e.g., a semiconductor memory, a magnetic storage device). Or an optical disk).

The above description is illustrative and not restrictive. Thus, it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.

Claims (13)

A lithographic apparatus,
A base frame forming a support structure of the lithographic apparatus;
An active base frame support configured to support the base frame on a ground plane, the active base frame support including an actuator configured to exert a horizontal force on the base frame.
The lithographic apparatus includes:
Give a configured controlled device to drive the actuator based on a signal representing the force exerted on the base frame supplied further Bei,
The signal representing the force on the base frame includes a setpoint signal of a support, the control device comprises a setpoint input, and the setpoint signal of the support is provided to the setpoint input of the control device. A lithographic apparatus , wherein the control device is configured to drive the actuator based on the setpoint signal . The lithographic apparatus according to claim 1 , wherein the control device is configured to use the setpoint of the support as a feedforward signal. The lithographic apparatus further comprises a horizontal force sensor configured to measure a horizontal force on the base frame, wherein the signal representing the force on the base frame comprises a horizontal force sensor signal of the horizontal force sensor. Wherein the control device comprises a horizontal force sensor input configured to receive the horizontal force sensor signal of the horizontal force sensor, wherein the control device drives the actuator based on the horizontal force sensor signal. configured, lithographic apparatus according to claim 1 or 2. The lithographic apparatus according to claim 3 , wherein the horizontal force sensor is included in the active base frame support. The base frame is provided with an accelerometer configured to sense an acceleration of the base frame, the signal representing the force on the base frame includes an accelerometer signal of the accelerometer, and the control device 2. The method of claim 1, further comprising an accelerometer input, wherein the accelerometer signal of the accelerometer is provided to the accelerometer input, and wherein the control device is configured to drive the actuator based on the accelerometer signal. the lithographic apparatus according to any one of 4. The lithographic apparatus according to claim 5 , wherein the accelerometer is located near the active base frame support of the base frame. Further comprising an additional accelerometer at or near the structure of the lithographic apparatus, wherein the signal representative of the force on the base frame comprises an output signal of the additional accelerometer, and wherein the control device comprises a further accelerometer Comprising an input, wherein the output signal of the further accelerometer is provided to the further accelerometer input of the control device, the control device being adapted to reduce the effect of resonance of the structure over the base frame. It said further responsive to the output signal of the accelerometer is configured to drive the actuator, lithographic apparatus according to any one of claims 1 to 6. Further comprising a force sensor disposed in a force path from a movable part of the lithographic apparatus to the base frame, wherein the signal representing the force applied to the base frame includes an output signal of the further force sensor; A device comprising a further force sensor input, wherein the output signal of the further force sensor is provided to the further force sensor input of the control device, the control device comprising: to reduce the effect of propagating the frame, in response to said output signal of said further force sensor driving said actuator, lithographic apparatus according to any one of claims 1 to 7. The ground plane is formed by a ground floor, the lithographic apparatus further comprises a ground floor accelerometer disposed on the ground floor, wherein the signal representative of the force on the base frame is an output of the ground floor accelerometer. A signal, wherein the control device comprises a ground floor accelerometer input, wherein the output signal of the ground floor accelerometer is provided to the ground floor accelerometer input of the control device, wherein the control device communicates through the ground floor. to reduce the influence of the propagation of the vibration propagating to the base frame Te, wherein configured to in response to the output signal of the ground floor accelerometer to drive the actuator, any one of claims 1 to 8 A lithographic apparatus according to claim 1. The lithographic apparatus further includes a normal force sensor configured to measure a normal force on the base frame, the control device includes a normal force sensor input, and the normal force sensor signal of the normal force sensor is the vertical force sensor. is supplied to the force sensor input, the control device is configured to drive the actuator using the normal force sensor signal, lithographic apparatus according to any one of claims 1 to 9. Said support,
A patterning device support that supports a patterning device that can apply a pattern to a cross-section of the radiation beam to form a patterned radiation beam;
A masking device configured to mask a portion of the patterning device;
Comprises one of the substrate table holding the substrate, the lithographic apparatus according to any one of claims 1 to 10. The lithographic apparatus according to claim 11 , wherein the horizontal direction of the active base frame actuator is a scan direction of a scan operation of the substrate table. The active base frame support comprises a stack of horizontal and vertical piezoelectric actuator and the horizontal and vertical force sensor, lithographic apparatus according to any one of claims 1 to 12.

Images